1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device, the method including planarization of the surface of a processed portion of an insulating film formed above a semiconductor substrate.
2. Description of the Related Art
In the formation of the damascene interconnection, the insulating film such as a silicon oxide film is processed using the reactive ion etching (RIE) and the following wet cleaning process or the like. The RIE and the wet cleaning or the like may roughen or damage the processed surface of the insulating film, thus adversely affecting the quality of the semiconductor device. Particularly, this tendency is significant for an insulating film having a lower density in response to the recent request for the lower dielectric constant (Low-k) of the insulating film and for an insulating film including a silicon oxide film added with a methyl group or the like. For example, the rough surface may cause a step disconnection of the barrier metal and thus degrade the interconnection reliability. The damage to the surface such as a methyl group elimination may further roughen the surface or increase the surface hygroscopicity in the cleaning process. The higher hygroscopicity may increase the dielectric constant and thus degrade the device characteristics. The damage may also cause metal corrosion and thus reduce the interconnection reliability.
To solve the issues, various methods have been proposed to use repair materials to recover the insulating films that are roughened or damaged or the like. For example, a surface-hydrophobicization composition as the repair material is brought into contact with the damaged layer by application by spin coating or evaporation by vacuum deposition. The composition may provide a hydrophobic film for recovery of the damaged surface (see, JP 2006-104418). The recovery film formation process by application by spin coating or vacuum deposition by evaporation may not, however, sufficiently planarize the damaged layer. This is for the following reasons. The film formation process may supply excessive repair materials resulting in residuals that may degrade the shape and the performance of the semiconductor device. In addition, a thin recovery film may reflect the asperity of the damaged layer or the like on the recovered surface.